Caster wheels are commonly used on industrial trucks and dollies and on some equipment to facilitate movement of goods and equipment from place to place. The wheels on such caster wheel suspensions are subjected to relatively high impact forces when they engage an obstruction, which impact forces increase as a function of increasing speed and weight or load, and decreasing wheel radius. Shock absorbing caster wheel suspensions such as disclosed in U.S. Pat. Nos. 2,738,542; 3,518,714 and 3,747,950 have heretofore been provided to reduce the transmission of impact forces from the ground engaging wheels to the suspension and to the load or equipment supported thereby. It has also been proposed, for example as shown in U.S. Pat. No. 3,066,950, to transport goods or equipment on over-the-road vehicles, while the goods or equipment are supported by shock absorbing wheel suspensions that rest on the bed of the over-the-road truck or trailer. The shock absorbing wheel suspensions used to support the load or equipment on the bed of the truck, function to absorb shock loads transmitted by the bed of the truck to the wheel of the shock absorbing wheel suspension, and dynamic or " G" loads transmitted by the load or equipment to the shock absorbing wheel suspension. However, when shock absorbing wheel suspensions are used to support a load or equipment on the bed of an over-the-road vehicle such as a truck or trailer having its own spring suspension, it has been found that the load or equipment sometimes goes into heavy vibration which can be damaging to some types of goods and equipment. Thus, while the prior shock absorbing wheel suspensions are adapted to absorb and reduce transmission to the load or equipment of relatively high impact shocks of a random nature, a periodic disturbing force from the truck bed, even of a low amplitude, can produce very large forced vibration in the load or equipment supported on the suspension apparatus when the frequency of the disturbing force approaches the frequency of natural vibration of the shock absorbing wheel suspension and the goods or equipment supported thereby. It has heretofore been proposed to transport some delicate equipment such as electronic equipment only in over-the-road vehicles having air bag suspensions, such as those provided on some household moving vans, and which are adapted to minimize the vibrations that are transmitted to the bed of the van. However, this markedly increases the cost of transporting the equipment over that which would be incurred if the goods or equipment could be shipped as a part of a load on regular freight hauling trucks